This project proposes a comprehensive clinical research project about individuals with Down Syndrome using data science approaches and several very large datasets with clinical records, such as IBM Watson Health MarketScan, Medicare, Medicaid, and Swedish National Registries. Specifically this project will conduct exploratory analyses to identify subtypes of people with Down Syndrome and other co-morbidities and the prevalence of these groups in the very large datasets, develop a predictive model of the life trajectories and future health trajectories of people in the different sub-types of Down Syndrome, and validate these predictive models in the smaller, deeper and richer Down Syndrome dataset compiled by Advocate Lutheran General Hospital (with one of the largest Down Syndrome clinics in the US).